The blood of exceptionally long-lived people shows crucial differences: ScienceAlert

Centenarians, once considered rare, are now commonplace. In fact, they are the fastest-growing demographic group in the world’s population, with numbers doubling roughly every decade since the 1970s.

How long people can live and what constitutes a long and healthy life has always been of interest. Plato and Aristotle discussed and wrote about the aging process over 2,300 years ago.

However, understanding the secrets behind exceptional longevity is not easy.

The aim is to decipher the complex interplay between genetic predisposition and lifestyle factors and their interaction over the course of a person’s life.

Now our current study, published in GeroSciencehas revealed some common biomarkers, including cholesterol and glucose levels in people older than 90 years.

Newborns and centenarians have long been of great interest to scientists because they could help us understand how to live longer and perhaps age more healthily.

To date, studies of centenarians have often been conducted on a small scale and focused on a select group, for example excluding centenarians living in nursing homes.

Huge data set

Our study is the largest study to date comparing the life-long biomarker profiles of exceptionally long-lived people and their shorter-lived peers.

We compared the biomarker profiles of people who lived to be over 100 years old with those of their younger peers and examined the association between the profiles and the chance of becoming a centenarian.

Our research included data from 44,000 Swedes who underwent a health examination between the ages of 64 and 99 – a sample of the so-called Amoris cohort.

These participants were then followed for up to 35 years using Swedish registry data. Of these people, 1,224 or 2.7% lived to be 100 years old. The vast majority (85%) of centenarians were female.

Twelve blood-based biomarkers related to inflammation, metabolism, liver and kidney function, and potential malnutrition and anemia were included. All of these have been linked to aging or mortality in previous studies.

The biomarker associated with inflammation was uric acid – a waste product in the body that is produced when certain foods are digested.

We also examined markers related to metabolic status and function, including total cholesterol and glucose, as well as those related to liver function, such as alanine aminotransferase (Alate), aspartate aminotransferase (Asat), albumin, gamma-glutamyltransferase (GGT), and alkaline phosphatase (Alp) and lactate dehydrogenase (LD).

We also looked at creatinine, which is linked to kidney function, as well as iron and total iron binding capacity (TIBC), which are linked to anemia. Finally, we also examined albumin, a biomarker associated with diet.

Insights

We found that, overall, those who made it to their 100th birthday tended to have lower glucose, creatinine and uric acid levels starting at age 60.

Although median values ​​for most biomarkers were not significantly different between centenarians and noncentenarians, centenarians rarely showed extremely high or low values.

For example, very few centenarians had glucose levels above 6.5 mmol/L or creatinine levels above 125 µmol/L earlier in life.

For many biomarkers, both centenarians and noncentenarians had values ​​that were outside the range considered normal in clinical guidelines.

This is likely because these guidelines are based on a younger and healthier population.

When we examined which biomarkers were associated with the likelihood of living to 100, we found that all but two (alate and albumin) of the 12 biomarkers were associated with the likelihood of living to 100 . This was true even after accounting for age, gender, and disease burden.

People in the lowest of the five groups for total cholesterol and iron levels had a lower chance of living to 100 compared to those with higher levels.

Meanwhile, people with higher levels of glucose, creatinine, uric acid and markers of liver function also reduced the chance of becoming a centenarian.

In absolute numbers, the differences for some biomarkers were rather small, for others the differences were somewhat larger.

For uric acid, for example, the absolute difference was 2.5 percentage points. This means that people in the group with the lowest uric acid levels had a 4% chance of living to 100, while in the group with the highest uric acid levels only 1.5% had a chance of reaching 100 years of age.

Although the differences we discovered were small overall, they suggest a possible connection between metabolic health, nutrition and exceptional longevity.

However, the study does not allow any conclusions to be drawn as to which lifestyle factors or genes are responsible for the biomarker values.

However, it can be assumed that factors such as diet and alcohol consumption play a role.

It’s probably not a bad idea to keep an eye on your kidney and liver values, as well as glucose and uric acid levels, as you get older.

However, chance probably plays a role at some point in reaching an extraordinary age.

But the fact that differences in biomarkers could be observed long before death suggests that genes and lifestyle could also play a role.

Karin ModigAssociate Professor, Epidemiology, Karolinska Institutet

This article is republished from The Conversation under a Creative Commons license. Read the original article.

An earlier version of this article was published in October 2023. A correction to a detail of the original study was published in November 2023.